Method and Arrangement for Controlling Uplink Transmit Power

1. A method in a User Equipment, UE, for controlling uplink transmit power to be used by multiple radio interfaces thereof, wherein at least one of the multiple interfaces is a cellular radio interface, the method comprising the steps of: storing information comprising a total transmit power threshold, which the US is not permitted to exceed when simultaneously transmitting over the multiple radio interfaces of the UE; receiving, from a network node, on the cellular radio interface, a transmit power control command indicating whether the UE is to increase, to decrease, or to maintain an uplink transmit power level on the cellular radio interface; and calculating, based on the received transmit power control command for the cellular radio interface, transmit power levels to be used for uplink transmissions on the multiple radio interfaces other than the cellular radio interface such that said total transmit power threshold is not exceeded.

2. The method according to claim 1 , wherein the stored information comprises profile information comprising at least one profile for a communication scenario indicating at least a first and a second radio interface of said multiple radio interfaces to be used associated with maximum transmit power levels to be used for the respective first and second radio interfaces, wherein the sum of the maximum transmit power levels to be used for the respective radio interfaces shall not exceed the total transmit power threshold.

3. The method according to claim 1 , wherein the method comprises the further step of: sending the stored information to the network node to enable the network node to take into account the total transmit power threshold when determining the transmit power control command to be sent to the UE.

4. The method according to claim 1 , wherein said total transmit power threshold is taken into account in the UE when calculating the transmit power levels to be used for uplink transmissions.

5. A method in a network node of a cellular communication network for controlling uplink transmit power to be used by a User Equipment, UE, transmitting on multiple radio interfaces, one of which is a cellular radio interface, the method comprising the steps of: receiving, from the UE, profile information indicating transmit power levels the UE is using on a subset of the multiple radio interfaces of the UE, and a maximum total transmit power threshold, which the UE is not permitted to exceed when simultaneously transmitting on the subset of the multiple radio interfaces; determining transmit power control commands for the UE indicating whether the UE is to increase, to decrease, or to maintain an uplink transmit power level on the cellular radio interface, while taking into account, by the network node, said profile information and the maximum total transmit power threshold, and sending the determined transmit power control commands to the UE.

6. The method according to claim 5 , wherein the received profile information comprises at least one profile for a communication scenario indicating at least a first and a second radio interface to be used associated with maximum transmit power levels to be used for the respective first and second radio interfaces, wherein the sum of the maximum transmit power levels to be used for the respective radio interfaces shall not exceed the total transmit power threshold.

7. A User Equipment, UE, for controlling uplink transmit power to be used by multiple radio interfaces of the UE, wherein at least one of the multiple interfaces is a cellular radio interface, the UE comprising: a memory for storing information comprising a total transmit power budget which the US is not permitted to exceed when simultaneously transmitting over the multiple radio interfaces of the UE; a receiver for receiving a transmit power control command from a network node on the cellular radio interface indicating whether the UE is to increase, to decrease, or to maintain an uplink transmit power on the cellular radio interface; and a power control unit for calculating, based on the received power control command for the cellular radio interface, transmit power levels to be used for uplink transmissions on the multiple radio interfaces other than the cellular radio interface; wherein the said total transmit power threshold is not exceeded.

8. The UE according to claim 7 , wherein the stored information comprises profile information comprising at least one profile for a communication scenario indicating at least a first and a second radio interface to be used associated with maximum transmit power levels to be used for the respective first and second radio interfaces, wherein the sum of the maximum transmit power levels to be used for the respective first and second radio interfaces shall not exceed the total transmit power threshold.

9. The UE according to claim 7 , wherein the UE comprises a transmitter for sending the stored information to the network node to enable the network node to take the total transmit power threshold into account when determining the power control command to be sent to the UE.

10. The UE according to claim 7 , wherein the power control unit is configured to take into account said total transmit power threshold when calculating the power levels to be used for uplink transmissions.

11. A network node of a cellular communication network for controlling uplink transmit power to be used by a User Equipment, UE, comprising multiple radio interfaces, the network node comprising: a receiver for receiving, from the UE, profile information indicating transmit power levels the UE is using on a subset of the multiple radio interfaces of the UE, and a maximum total transmit power threshold, which the UE is not permitted to exceed when simultaneously transmitting on the subset of the multiple radio interfaces; a power controller for determining transmit power control commands for the UE indicating whether the UE is to increase, to decrease, or to maintain an uplink transmit power level on the cellular radio interface, while taking into account said profile information and the maximum total transmit power threshold; and a transmitter for sending the determined transmit power control commands to the UE.

12. The network node according to claim 11 , wherein the received profile information comprises at least one profile for a communication scenario indicating at least a first and a second radio interface to be used associated with maximum transmit power levels to be used for the respective first and second radio interfaces, wherein the sum of the maximum transmit power levels to be used for the respective radio interfaces shall not exceed the total transmit power threshold.

13. The network node according to claim 11 , wherein the network node is a base station.